I'm trying to drive two MOSFETs through a pulse transformer. I'm using the "Power Supply Cookbook – Second Edition" book from Marty Brown. According to the book the formula to calculate the number of turns of the 1:1 driver is:
N = Vcc/(4×F×Bmax×Ae)
In my case Vcc = 15V, F=200KHz, estimated Bmax to 0.1T (I'm using a 15mm toroidal core from a PC power supply) and Ae=0.000123m^2 so this gives me 10 turns. The book recommends toroidal cores from 10 to 15mm of diameter. This is the core I built, 10 turns on primary and the same turns on both secondaries in opposite directions:
I tried using a Push-Pull driver using BC548 and BC558 but at 200KHz it works really bad, a duty cycle on base of 80% gives me between 10% or 20% on the output, this doesn't happen at lower frequencies like 50KHz. So I'm using an IR2110, I know it's a high-side driver too but I'm using it as two low-side driver. This is the schematic:
And this one:
But when I connect the output of the IR2110 to the pulse transformer I get a current consumption of about 400mA to 600mA and the output on the secondaries are very distort, far away from a square pulse. The IR2110 inputs are driven from a microcontroller that generates a half-bridge output.
Is there anything wrong with my design? What do you suggest?